There is disclosed in U.S. Pat. No. 4,845,589 a bus bar assembly comprising a frame in which circuit modules are slidable on rails towards and away from a power bus bar, the circuit modules being arranged one above the other. Each module has receptacle in the form of a tulip contact for receiving the bus bar when the module, which is in the form of a drawer, has been slid to a home position in the frame. The bus bar is incorporated in the frame and each receptacle is secured to a guide fork for guiding the receptacle into mating relationship with the bus bar. The guide fork is fixed to a slide block mounted on the module for sliding movement transversely of the rails to take up play between the module and the rails. Drawer connector assemblies comprising a pair of mating electrical connectors are also disclosed in U.S. Pat. No. 4,664,456 and U.S. Pat. No. 4,761,144 but these assemblies do not include the bus bar therein.